Fire-resistant structural members for buildings



p 1969 A. J. MCGEE, JR

FIRE-RESISTANT STRUCTURAL MEMBERS FOR BUILDINGS Filed Jan. 10, 1967 2 Sheets-Sheet l Mar/m sap/21y /Z INVENTOR flzmzwx J M'ke, J2

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ATTORNEY 2 Sheets-Sheet 2 ATTORNEY Sept. 2, 1969 A. J. MOGEE, JR

I FIRERESISTANT STRUCTURAL MEMBERS FOR BUILDINGS Filed Jan. 10, 1967 United States Patent 3,464,172 FIRE-RESISTANT STRUCTURAL MEMBERS FOR BUILDINGS Andrew J. McGee, Jr., Rte. 1, Coward, S.C. 29530 Filed Jan. 10, 1967, Ser. No. 608,295 Int. Cl. E04b N94 US. Cl. 52-168 3 Claims ABSTRACT OF THE DISCLOSURE A structural member for use in building construction, wherein all of the weight-bearing portions of the member subject to stress have internal cooling passages constructed and arranged to receive water. The structural member is thus rendered fire-resistant and may also constitute a part of a fire extinguishing sprinkler system as when sprinkler heads are provided at spaced intervals along the member in communication with the internal cooling passages.

Background of the invention The invention herein pertains to self-cooling fire-resistant structural members of various forms used in building construction and to sprinkler systems which may be integrated with the fire-resistant members so as to eliminate the necessity for separate piping.

Steel structural members for the support of floors, roofs and the like are ideal under normal conditions, but when fire occurs and excessive temperatures are created, steel roof trusses and beams frequently sag and may cause entire buildings to collapse. A number of fire fighters and other people lose their lives each year because of this characteristic of metal supporting members.

Summary of the invention According to the present invention, a metal truss, rafter, beam or the like is equipped with a water inlet and a water outlet and all load bearing sections of the structural member have cooling passages which communicate directly or indirectly with the inlet and outlet. The outlet may be in the form of a sprinkler head which will be activated by heat. The member may be constantly water-filled or may be normally dry and filled automatically with cooling liquid in the presence of heat. The invention is applicable to various forms of load bearing structures.

The invention fully overcomes the prior art deficiencies by the provision of structural members which will not sag, bend or fail in the presence of high temperatures and which are therefore truly fire-resistant. Additionally, the members constructed according to the invention are capable of providing an inexpensive fire extinguishing system requiring no separate or additional piping whatsoever. The fire extinguishing feature is optional.

Brief description of the drawings FIGURE 1 is a side elevational view, partly in section and partly broken away, of a truss constructed in accordance with one preferred embodiment of the invention;

FIGURE 2 is an enlarged transverse vertical section taken on line 2-2 of FIGURE 1;

FIGURE 3 is a fragmentary side elevational view of a truss or the like according to a modification of the invention;

FIGURE 4 is an enlarged fragmentary vertical section taken on line 4-4 of FIGURE 3;

FIGURE 5 is a side elevational view, similar to FIGURE 1, showing another modification;

FIGURE 6 is a fragmentary side elevational view of a further modification; and

FIGURE 7 is a vertical section taken on line 7-7 of FIGURE 6.

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Description of the preferred embodiments Referring to the drawings, wherein like numerals designate like parts, and with particular reference to FIGURES 1 and 2, the numeral 10 designates a structural member such as a metal roof truss having each end equipped with a foot plate 11 to rest upon a wall 12 or upright. The configuration of the member or truss 10 may vary widely under the invention and the drawings are illustrative only insofar as shape is concerned. In the embodiment shown, the truss 10 has top and bottom horizontal members 13 and 14, interconnecting end inclined sections 15 and a plurality of diagonal braces 16, as indicated. Preferably all sections or elements of the truss 10 are tubular and communicating, as clearly indicated in FIGURE 1.

At a convenient location, preferably near one end of the truss, a water inlet pipe 17 under city water pressure leads into the bottom tubular section 14. If desired, the pipe 17 may be connected into another portion of the truss. The inlet pipe 17 carries cooling water to all sections of the truss 10, and in the embodiment under consideration, the truss will be normally water-filled at all times.

As an optional feature, preferably the lower horizontal section 14 is equipped at intervals with fire extinguishing sprinkler heads 18. These heads may be of any conventional heat-sensitive type, for example the type disclosed in expired United States Patent 1,834,319 to Russell. As is well known, in the presence of sufficient heat, a fusi ble link melts on the sprinkler head 18 and the water within the truss 10 will be discharged under pressure from each sprinkler head. In this manner, the fire-resistant truss or structural member may optionally serve the dual function of a built-in fire extinguishing sprinkler system, without the necessity for any separate piping or installation except for the mounting of the sprinkler heads 18 at the desired intervals.

When a fire occurs, cooling water will continuously flow through all sections of the truss 10 and the truss will resist bending or sagging and retain its proper shape and after the fire will still be a sound member. The advantages of the construction will be apparent to those skilled in the art.

FIGURES 3 and 4 of the drawings show a modification wherein a truss or member 19 is constructed generally in accordance with the previous embodiment but is adapted to have its internal communicating passages normally dry or empty until a fire occurs. A water inlet pipe 20 communicates with the lower horizontal bar 21 of the truss 19 and all other parts of the truss communicate with each other and with the bar 21. The pipe 20 contains a meltable plug 22 which normally prevents the admission of water into the truss 19. When the temperature rises due to a fire, the plug 22 will quickly melt and water will be admitted to the truss and the latter quickly becomes filled and self-cooling and therefore fireresistant. Preferably, although not necessarily, the truss 19 is provided with a number of small spaced discharge openings 23, for the escape of steam and also to allow some water circulation during the fire. If preferred, one larger outlet opening may be provided near the end of the truss remote from the inlet 20 or at any other desired point. The advantages of the member or truss in the presence of fire are essentially those specified in connection with the prior embodiment.

FIGURE 5 shows a further modification, wherein a truss 24 constructed generally like the trusses 10 and 19 has a single water inlet pipe 25 near one end thereof, preferably containing a meltable plug 26 for the purpose already described. The lower section 27 is provided with a web 28 near one side of the inlet pipe 25, and on the other side of this web, a water outlet pipe 29 is connected in the truss in communication with its interior passages. 7

fluid-tight cooling liquid chambers 34 on opposite sidesof the main web 35 of I-beam 30. The extreme ends of the chambers 34 are closed by suitable walls 36. As shown, a water inlet pipe 37 communicates with one cooling chamber 34 and, if desired, the pipe 37 may be equipped with a melt plug similar to the plugs 22 and 26. This is optional. The main web 35 has a through opening 38 through which the two chambers 34 communicate so that both may be filled with water. The chamber remote from the pipe 37 :preferably has an outlet opening 39 so that there may be circulation through the entire member at the time of a fire. Variously shaped structural beams, rafters and like members are rendered completely fire-resistant in substantially the same manner. It is thought that the advantages of the invention should now be fully apparent to those skilled in the art without the necessity for a further description.

I claim:

1. A fire-resistant load-bearing structural member for use in building construction comprising a metal body portion having an internal passage for cooling fluid which extends substantially through all load-bearing portions of the member, said metal body portion comprising a beam having a central web and closure plates spaced from opposite sides of the web whereby said internal passage is divided into two sections on opposite sides of the web, said passage section extending substantially for the length of the beam, the central web containing a through opening establishing communication between the passage sections on opposite sides of the web, and a connection in said passage ,through which the cooling fluid may enter the passage to substantiallyfill the interior of the beam with cooling fluid. l

2. The structure of claim 1, and an outlet for cooling fluid leading from said passage at a point remote longitudinally from said connection, whereby cooling fluid may circulate continuously through said passage including both passage sections.

3. A fire-resistant load-bearing structuralmember for use in building construction a metal body portion having an internal passage for cooling fluid which extends substantially through all the load-bearing portions of the member, said metal body portion being inthe form of a truss including upper and lower tubular longitudinal truss bars and tubular diagonal struts interconnecting the upper and lower bars and communicating with both of said bars, said internal passage extending continuously through said bars and through all of said struts, whereby cooling of the entire truss is achieved, a connection with the truss leading into said passage through which the cooling fluid is directed into the passage, a web formed across said passage in one of said bars, said connection being on one side of the web in said one bar, and an outlet connection from said passage in said one bar on the other side of said web thereby allowing continuous circulation of cooling fluid in all portions of said member.

References Cited UNITED STATES PATENTS 254,253 2/ 1882 Ashcroft. 2,734,583 2/1956 Milan 52-220 X 2,809,074 10/ 1957 McDonald 239209 3,050,134 8/1962 Multin 52-220 3,104,060 9/1963 Bricmont 239-209 M. HENSON WOOD, JR., Primary Examiner M. Y. MAR, Assistant Examiner US. Cl. X.R. 169-16; 239-209 

